Neffos C5L Replacement Battery 3.8V 1750mAh NBL-45A2000

Neffos C5L Series — 3.8V Li-ion Replacement Battery (NBL-45A2000)

This is a 3.8V, 1750mAh (6.65Wh) Li-ion replacement battery for the Neffos C5L smartphone. It fits the C5L, C5L Dual SIM, TP601E, and TP601C. Use it when the original cell no longer holds a charge or shuts the phone down unexpectedly.

• TP601 platform fit: The C5L, C5L Dual SIM, TP601E, and TP601C all share the same battery bay dimensions, connector orientation, and BMS communication protocol. The NBL-45A2000 part number covers all of these variants — the underlying cell spec and NTC thermistor pinout are identical across the range.
• Bench tested on actual hardware: We ran this cell on a TP601C unit through three full charge-discharge cycles. The BMS accepted the new cell without handshake errors, the protection circuit tripped correctly at low-voltage cutoff, and charge current stepped down normally as the cell approached capacity.
• Fuel gauge recalibration on first use: After installation, disable fast charging and run one complete discharge down to auto-shutdown, then charge fully without interruption. This gives the fuel gauge IC a clean reference curve against the new cell — skipping this step is the main cause of erratic percentage readings in the first week.

Sudden shutdown at 20–30% on the Neffos C5L after a cell swap

A new cell has a slightly different voltage-to-capacity curve than the degraded cell the fuel gauge IC was calibrated against. When the phone reads 25%, the actual cell voltage under modem or screen load may already be dropping toward the BMS cutoff threshold near 3.0V. The phone shuts down not because the battery is faulty, but because the gauge IC is firing a low-voltage interrupt based on stale calibration data. One full discharge-to-shutdown followed by an uninterrupted full charge resets the coulomb counter reference and resolves this within one or two cycles.

Phone feels warm near the battery during the first few charges

A new cell starts with higher internal impedance than a cell that has been through several cycles. The charge IC pushes current into that higher resistance, which generates more heat than you would see after the cell has broken in. This is normal for the first two to three charges and not a sign of a faulty cell or a failing charge IC. If the phone remains warm beyond the third full charge cycle, check that the back cover is seated flat — a lifted cover traps heat and can sustain elevated temperatures past the break-in period.